文章基本信息

标题：Infrared spectra of complex organic molecules in astronomically relevant ice matrices
其他标题：I. Acetaldehyde, ethanol, and dimethyl ether
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作者：J. Terwisscha van Scheltinga ; N. F. W. Ligterink ; A. C. A. Boogert 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2018
卷号：611
DOI：10.1051/0004-6361/201731998
语种：English
出版社：EDP Sciences
摘要：Context.The number of identified complex organic molecules (COMs) in inter- and circumstellar gas-phase environments is steadily increasing. Recent laboratory studies show that many such species form on icy dust grains. At present only smaller molecular species have been directly identified in space in the solid state. Accurate spectroscopic laboratory data of frozen COMs, embedded in ice matrices containing ingredients related to their formation scheme, are still largely lacking.Aim.This work provides infrared reference spectra of acetaldehyde (CH3CHO), ethanol (CH3CH2OH), and dimethyl ether (CH3OCH3) recorded in a variety of ice environments and for astronomically relevant temperatures, as needed to guide or interpret astronomical observations, specifically for upcomingJames WebbSpace Telescope observations.Methods.Fourier transform transmission spectroscopy (500–4000 cm−1/20–2.5μm, 1.0 cm−1resolution) was used to investigate solid acetaldehyde, ethanol and dimethyl ether, pure or mixed with water, CO, methanol, or CO:methanol. These species were deposited on a cryogenically cooled infrared transmissive window at 15 K. A heating ramp was applied, during which IR spectra were recorded until all ice constituents were thermally desorbed.Results.We present a large number of reference spectra that can be compared with astronomical data. Accurate band positions and band widths are provided for the studied ice mixtures and temperatures. Special efforts have been put into those bands of each molecule that are best suited for identification. For acetaldehyde the 7.427 and 5.803μm bands are recommended, for ethanol the 11.36 and 7.240μm bands are good candidates, and for dimethyl ether bands at 9.141 and 8.011μm can be used. All spectra are publicly available in the Leiden Database for Ice.
关键词：Key wordsenastrochemistrymethods: laboratory: moleculartechniques: spectroscopicmolecular processes